If you have an older chainsaw, you’ve probably heard it say this before: “Help, Help! cough, umpfh, vrooooommmmm! cough, sputter, death.” I’ll walk you through the steps of rebuilding a carburetor andl bringing a Stihl 026 chainsaw back to life.
Maybe I shouldn’t lead off with this, but my Husquvarna 55 has never given me trouble… Just sayin’.
A Little Back Story
The 026 was given to me. Yes, pretty cool, right? It was in a box… In pieces… With enough oil impregnated swarf packed into each nook and cranny to make a dozen toxic candles. The first step was clear. CLEAN!!! Tooth picks, nylon brushes, and a steady supply of compressed air were the tools needed for this project. After replacing the spark plug and putting some fresh gas in the tank, she was purring like a kitten.
Fast forward about a year and things aren’t so dandy. Once the saw would turn over, it would immediately die. Nothing is more frustrating.
So what’s the problem? Well, I had a hunch that the carburetor needed to be rebuilt, so I tore it apart and what do ya know. The diaphragm was torn… This is obviously an issue. Lets hope it runs like a top when I get it back together.
I found my carburetor rebuild kit online for less than $10. If you try getting these parts from your local chainsaw shop… Well lets just say you shouldn’t even bother calling because it will be at least 3 times more expensive.
Rebuilding a carb is pretty straight forward. Keep track of the way things come apart. Catch the spring that wants to go airborne from the needle valve. Give everything a good soak of carb cleaner and then reassemble. Easy, right? Well, just in case you like pictures as much as I do, you’re in for a treat.
What You Need for a Carburetor Rebuild
- A Carburetor (you guessed that one right?)
- Rebuild Kit
- Carb Cleaner
- Small Screwdrivers
- Standard Size Screwdrivers
- Box Wrenches, inch or metric depending on saw
- Paper Towels
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Where’s the Carburetor?
Rebuilding the Carb!
Dissassembly
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Remove Rocker Arm & Needle Valve
There is a rocker that is held in place with a philips head screw. Place your thumb over the side of the rocker that is closest to the center of the carb. Once you’ve removed the screw, that spring wants to hide under the pile of dust in your shop where you will never find it again. Slowly lift your thumb and collect the rocker arm, spring, screw, and needle. A magnetic tray is a great place for these to live until you’re ready for them.
Carb Cleaner To The Rescue!
With all of the gaskets and such removed, you’re ready for the carb cleaner. Soak this thing down and let the cleaner drain through all the passages and you should be good. Make sure to spray every nook and cranny. I did this step one morning before heading off to work. That evening I got into replacing the components. I’d let the carb sit at least 30 minutes to allow everything to dry off before reassembling.
Reassemble The Carburetor
Start with putting the screen back in (if you took it out). A pencil eraser works quite well to push the screen into place. The screen will (at least mine was) be creased a bit. Put the screen in place similarly to a coffee filter. Those of you that are Keurig only folks are just screwed unless you remember what a coffee filter is… I’m a french press kinda guy myself, but that’s just a bit off topic.
Rocker Arm & Needle Valve Reinstalled
I promise that’s the hardest part of this whole post.
New Gaskets
Moving on to gaskets. Basically you just line up the holes and lay them down in the opposite order that you removed them. Follow along with the pictures if you don’t remember. Also, I did actually put all four screws back, just not for this picture… Not sure why.
Carb Back In The Saw!
Alright! The carb is back together. Now just slam that bad boy on the saw and let ‘er rip! First on the list is to reconnect the gas line. The gas line is the longer of the two tubes. It hooks up the the black barb. Now is also the time to reattach the throttle wire. Any words I used to describe it’s orientation would be futile, so hopefully the picture will get you there.
Hook Up The Throttle
The last step before slapping the covers back on is to reattach the throttle wire to the trigger. The throttle mechanism is a two part system which requires you to be gripping the handle to rev the motor. There is a spring that wants to poke your eye out. Push it down into the handle and place the remaining throttle component on top of the spring. There will be a little indention that will hold this spring in place. Once that’s done, reinstall the handle cover and you’re done.
As long as you didn’t turn any of the adjustment screws on the carburetor in the process, you should be good to go.
Unfortunately my troubles did not end with the carburetor rebuild. The saw was dreadfully low on compression and would not run.
I discuss how to completely rebuild the crankcase and top end in my post:
A Dying Chainsaw’s Last Words: Top End Rebuild.
Thanks for reading, and feel free to leave any questions or comments.
Robert Patrick says
I am really impressed by reading this article. Interesting post and I really like your take on the issues. Thanks for sharing this blog
Mark says
Mike,
Thanks so much for this clear post. This is the way the internet was in the early days. Folks helping each other out without trying to sell them something. You rock sir!
I’ve done this before but had some doubts as it was years ago. Your clear (and humerous) instructions really helped.
As russell fischels experienced, the needle in my kit was wrong for my carb. (much larger than original).
For reference it was a kit labeled ‘Forester’ #18157.
I also looked at the original with a magnifying glass and saw no grooves so I also re-used the old one. Odd that they don’t give you a new spring as springs do lose some tension over time…
My only suggestion would be to add an edit: remove and cleane the low and high speed adjustment screws as well as their ports.
Thanks again!!
Mike says
Thank you for the kind words Mark! I’m glad the article was helpful! Cheers!